21.87 is what percent of 30 - step by step solution

To get the solution, we are looking for, we need to point out what we know.

1. We assume, that the number 30 is 100% - because it's the output value of the task.
2. We assume, that x is the value we are looking for.
3. If 100% equals 30, so we can write it down as 100%=30.
4. We know, that x% equals 21.87 of the output value, so we can write it down as x%=21.87.
5. Now we have two simple equations:
1) 100%=30
2) x%=21.87
where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:
100%/x%=30/21.87
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 21.87 is what percent of 30

100%/x%=30/21.87
(100/x)*x=(30/21.87)*x       - we multiply both sides of the equation by x
100=1.3717421124829*x       - we divide both sides of the equation by (1.3717421124829) to get x
100/1.3717421124829=x
72.9=x
x=72.9

now we have:
21.87 is 72.9% of 30